Foul detecting system with transistor output switch



Feb. 23, 1965 R. E. BRowN r-:TAL

FOUL DETECTING SYSTEM WITH TRANSISTOR OUTPUT SWITCH Filed April 27, 19622 Sheets-Sheet 1 M n, P

INVENToR iwi wnwwu Mom.

NMI

AyMoA/o E. BROWN 7Z/oMAs Afef/NALE ATTONE Y j 3,170,689 FOUL DETECTINGSYSTEM WITH TRANSISTGR OUTPUT SWITCH f g,

Raymond E. Brown, l765 Hazelvalley, Hazelwood, Mo.,

and Thomas A. Crngnale, Woodson Terrace, Mo.

(9201 Gedde, St. Louis 34, Mo.) y

Filed Apr. 27, 1962, Ser. No. `190,536 3 Claims. `(Cl. 273-50) Thisinvention relates inV ,general to foul ldetection systems for use inbowling lalleys and the like, and more particularly to foul detectionsystems in which all controls are electronic andelectronicallyope'rated.

At the present time, foul detection systems .as used in bowling alleysare composed of a combination of electrical and mechanical devices,including relays, gears, motors, mechanically-operated switches and thelike. Because of the large number of moving parts associated therewith,this equipment-inherently requires repeated maintenance in order Vto bekept in satisfactory operating condition, which said maintenance resultsin vunusually highcost to the owners and operators of such equipment. Itis the primary object of the present invention to provide a fouldetection system which, except for a sound producer, is purelyelectronic in structure and operation and which employs no other movingparts.

It is also an object of the present invention to .provide a fouldetection system of the typedescribed in which the said system canelectronically distinguish between the passage of a bowling ballor thelike over a foul line and the passage. of ahuman foot over the said foulline.

With the above and Aother objects in view, which will become apparentupon vreading the lfollowing description, our invention resides -in thenovel features of -form, conf struction, arrangement and combination ofparts 'presently described and pointed out in the claims.

In the accompanying drawings:

FIGURE 1 is a schematic block diagram of anembodin ment of ourinventionas used in a pair of adjacent bowling lanes;

FIGUREZ is an electrical schematic diagram thereof;`

FIGURE 3 is anend view of ,a typical pair of bowling lanes showing theposition of the beams with'respect to the floor and therails. Y

Referring now in more detail andby reference character to the drawings,which illustrate va preferred embodiment vof the present invention, Adesignates a bowling alley comprising a pair of adjacent bowling lanes10, 12,

denedby spaced parallel gutter rails 14, 16, 18, and rcto v50 spectivelyprovided with lregulation foul lines 20, 22, the crossing ofwhich willcause that particular bowler forfeit his score for that particularthrow. n

Mounted on the rail 16 and respectively presented to the complementaryrails 14, 18, in alignment with the foul lines 20, 22, respectively, areconventional light beam projectors 24, 26, which are conventionallycoupled to a source of electrical power 28 and which project beams R andR', respectively, across the lanes 10, 12, above the foul lines 20, 22,respectively. Mounted in the rail 14 in alignment with the foul line 20and the vbeam projector 24, is a photocell 30 provided with a cathode 32which is connected toia source of negative potential designated as `Band a plate 34 which is connected to the `input 'terminall 36 of acurrent amplifier 38, also prot vided with an output terminal 40;vsimilarly mounted'in the rail 18 and 'in alignment with the foul Vline22 and the lbeam projector `26v is a photocell 42 including a cathode`44connected to B, and a plate 46 which is the input terminal 54 of rvaunilateral isolator 56 having 3,170,689 Patented Feb. 23, 1965 ice alsoan output terminal 58 4and an indicator light igniting circuit 60comprising a single-shot multivibrator net- `work 62, a currentamplifier 64,'and an electronic switch .n fascia board F above the lanes10, 12.y

Similarly connected to the output terminal 52 of th i n currentamplifier l50 is the input terminal 70 of a uni,

lateral isolator 72, also having an output terminal 74, and an indicatorlight igniting network 76 comprising a single-shot multi-vibratornetwork v78, a current amplifier 80, and an electronic switch 82, and anindicator light 84, all connected in series respectively'from the outputterminal 52 of the current amplifier 50.

The output terminals 58, 74, of the unilateral isolators V56, 72,respectively, are connected together and to a bell ringing circuit 86comprising a single-shot multi-vibrator Vnetwork 88, a current amplifier90, and an electronic switch 92, and a bell `94, all connected inseries.

The current amplifier 38 includes a potentiometer 100,

the tap of which is electrically connected to the base of a transistor102 and the input terminal 36. One end of the potentiometer 100 isconnected through a resistor 104 to B- and the other end of thepotentiometer 100] is connected through aresistor 106 to a source ofpositive potential designated as B+. The collector of the transistor 102is directlyv connected to B and the emitter of the transistor 102 isconnected to the base of a second transistor 108 and through a resistor110y to B+. The emitter of the transistor 1.08 is connected'to a sourceof zero potential, or ground, and the collector thereof is connected tothe output terminal 40 of the current amplier 38 and through ,aresistor112 to B+.

Connected to the input terminal 36 of the current-amplifier 38 is acapacitor 114, one plate of which is connected to ground. Connected tothe output terminal 40 of the current amplifier 38 is a variablecapacitor 116, also having one of its plates `connected to ground.

Connected to the output terminal 40-of the current amplifier 38 is thesingle-shot multi-vibrator 62 compris-` ing a transistor 118 having ,abase which is connected to the output terminal 40 vthrough a resistor120 4and which is also connected to B+ through ya resistor y122. The

emit-ter of the transistor 118' is grounded and the colofthe transistor130 is connected to ground and the'collector is connected to B-through aresistor.,136, to ground through a capacitor 138, and to the base of thetransistor 118 through a resistor 140. y

The current amplifier 64 comprises a transistor y142, the base of whichis connected to the collector ofthe transistor 130 through a resistor144 and to B+ through connected to theinput terminal 48 of a currentamplifier.l

a resistor 146. The emitter of the transistor 142 is grounded and thecollector of the transistor 142 is connected to` B- through tworesistors, V148, 150,*connected to each other in series. y

Connected to the common juncture of the resistors 148, 150, is the baseof a'transistor 152, 1the emitter of which is directly'connected to B+,and the collector of which is connected to the -base ofa secondtransistor 154 through a resistor 156. The base of the transistor 154 isalsoconnected to B+ through a resistor 158. vThe emitter of thetransistor 154 isV connected directly to ground, and the collector ofthe transistor154 is eonnected through the indicator light 68 tooneterminal of Y the secondary coil 1600i a step-down transformer 162,

the other terminal of the secondary coil 160 being connected to ground,for purposes presently more fully to appear.

TheA electrical circuitry for the current amplifier 50 is identical withthe electrical circuitry for the current wamplier 38, and similarly thecircuitry for indictor igniting networks 60 and 76 are also identical. u

The current amplifier 50 includes a potentiometer 200, 'the tap of whichis electrically connected to the base of a transistor 202 and the inputterminal 48. One end of the potentiometer 200 is connected through aresistor 204 to B- and the other end of the potentiometer 280 isconnected through a resistor 206 to B+. The collector of the transistor202 is directly connected to B- and the emitter of the transistor 202 isconnected to the base of a second transistor 208 and through a resistor210 to B+. The emitter of the transistor 208 is connected to a source ofzero potential, or ground, and the collector thereof is connected to theoutput terminal 52 of the current amplifier 50 and through a resistor212 to B-. Connected to the input terminal 48 of the current amplirfier50 is a capacitor 214, one plate of which is connected to ground.Connected to the output terminal 52 of the current amplifier 50 Vis avariable capacitor216,

one plate of which is connected to ground.

Connected to the output terminal 52 of the current amplifier 50 is thesingle-shot multi-vibrator 78 comprising a transistor 218 having a basewhich is connected to the output terminal 40 through a resistor 220 andwhich is also connected to B+ through a resistor 222. The emitter of thetransistor 218 is grounded andthe collector is connected to B- through aresistor 224. Also connected to the collector` of the transistor 218through a capacitor 226 and a resistor 228 is the base of a transistor230, which said base is also connected to B- through a resistor 232 inseries with a potentiometer 234 having a tap which is also connected toB-. The emitter of the transistor 230 is connected to ground and thecollector is connected to B- through a resistor 236 to ground through acapacitor 238, and to the base of the transistor 218 through a resistor240.

The current amplifier 80 comprises a transistor 242, the base of whichis connected to the collector of the transistor 230 through a resistor244 and to B+ through a resistor 246. The emitter of the transistor 242is grounded and the collector of the transistor 242 is connected to B-`throughtwo resistors, 248, 250, connected to each other in series. l

Connected to .the common juncture of the resistors 248, 250 is the baseof a transistor 252, the emitter of which is directly connected to B-and the collector of which is connected to the base of a secondtransistor 254 through a resistor 256. The base of kthe transistor 254is also connected to B+ through a resistor 258. The emitter of thetransistori254 is connected directly to ground, and the collector of thetransistor 254 is connectedthrough the indicator light 84 to oneterminal of the secondary coil 260 of a step-down transformer 262, theother terminal of the secondary coil 260 being con-V nected to ground,for purposes presently more fully to appear.

The unilateral isolators 56, 72, comprise two diodes 300, 382, having acommon anode connection 304 in the manner shown in FIGURE 2. Connectedto the common anode connection 304 is the bell ringing circuit 86 which,save for the substitution of the bell 96 for the indicator light, 68, isidentical in structure and operation to the indicator light ignitingnetwork 60. v

Connected to the common connection of the anodes of the diodes 300, 302,is the single-shot multi-vibrator network 88 comprising a transistor 318having a base whichv isv connected to the anode common connectionthrough a resistor 320 and which is also connected to B+ through aresistor 322. The'emitter ofthe transistor 318 is grounded and thecollector is connected to B- through a resistor 324. Also connected tothe collector of the transistor 318 through a capacitor 326 and aresistor 328 is the base of a transistor 330, which said base is alsoconnected to B- through a resistor 332 in series with a potentiometer334 having a tap which is also connected to B-. The emitter of thetransistor 330 is connected to ground and the collector is connected toB- through a resistor 336 to ground through a capacitor 338, and to thebase of the transistor 318 through a resistor 340.

The current amplifier 90 comprises a transistor 342, the base of whichis connected to the collector of the transistor 330 through a resistor344 and to B+ through a resistor 346. The emitter of the transistor 342is grounded and the collector of the transistor 342 is connected to B-through two resistors, 348, 350, connected to each other in series.

Connected to the common juncture of the resistors 348, 3511, is the baseof a transistor 352, the emitter of which is directly connected to B-and the` collector of which is connected to the base of a secondtransistor 354 through a resistor 356. The base of the transistor 354isalso connected to B+ through a resistor 358. The emitter of thetransistor 354 is connected directly to ground, and the collector of thetransistor 354 is connected through the bell 36 to one terminal of thesecondary coil 360 of a step-down transformer 362, the other terminal ofthe secondary coil V360 being connected to ground, for purposespresently more fullyy to appear.

By way'of illustration, and not of limitation, the following chartdiscloses component magnitudes which we have found yields an acceptablefoul detecting system:

Table A Resistors: Y Magnitude (ohms) 104, 204 1.2 meg. 106, 206 1.2meg. 110, 210 22K. 112, 212 6.8K. 120, 220, 320 6.8K. 122, 222, 322 27K.124, 224, 324 560. 128, 228, 328 1K. 132, 232,332 22K. 136, 236, 3361.5K. 140, 240, 340 10K. 144, 244, 344 10K. 146, 246, 346 27K. 148, 248,348 1.5K. 150, 250, 350 6.8K. 156, 256, 356 150. 158, 258, 358 1K.

Potentiometers z Y Ma gnitudc 100, 208 -O-l megohm. 134, 234, 334-'010K.

ransistors: TYP@ 102, 202 2N 414. 108, 208 2N 414. 118, 218, 318 2N 414.130, 230, 330 2N 414. 142, 242, 342 2N 414. 152, 252, 352 2N 414. 154,254,354' 2N 277.

Capacitors: j

114, 214 .O3 rnicrof.l 116, 216 5-15 microf. 126, 226 500 microf. 326 rmicrof. 138, 238, 338 f 10 microf.

Transformers:

162, 262, 362 Primary 117 `V., Secondary, 12 v., Y'oltages:

B+ to ground 6 v.

B- to ground -6 v It should be here noted that the current amplifiers:38, 50, are each identical, one to the other; the single-shotmulti-vibrator networks 62, 78, and 88 are each identical, one totheother; the current amplifiers 64, 80, and 90, are each identical onetothe other; the electronic switches 66, 82, and 92, are each identicalone to the other; and the indicator lights 68, and 841 and the bell 94are each respectively connected to the switches 66, 82, and 92, and thesecondary coils 1.60, 260, and 360, of the transformers 162, 262, 362'.l In operation, current always flows from B+' to B- through the resistor106,r the potentiometer 100, and the resistor `104; in addition, thecurrent also flows from BH- to B- through the resistors 122, 120, and112; furthermore, current always ows from B+ to B- through the resistors122, 140, and 136; also, current flows from B+ to B-` through theresistors 146, 144, and 136.

The magnitudes of the resistors 104 and 106 and the potentiometer 100are selected so that the transistor 102 will always be in conduction.With the light beam R always striking the photocell 30, current will besupplied to, the base of the transistor 102` from the photocell 30, and,as long as that beam R is being received by the photocell 30, thevoltage at the emitter of the transistor 102 and the base of thetransistor 108 is at its least positive value. With the base of thetransistor 108 at its least positive value, the transistor 108 isplacedin a state 'of conduction, thereby increasing the voltage dropacross resistor 112 and reducing the amount of current that flowsthrough the resistors 122 and 120. With the current througlrthe resistor122 reduced, the voltage at the base of the transistor 118 becomespositive, the transistor 118 becomes cutoff, and the transistor 130 isbiased to saturation through the potentiometer 134 and the resistor 132.

With the transistor-.130 in the saturated condition, the voltagey at thecollector of the transistor 130 is at its most positive voltage, andthecurrentwhich flows from Bei-to B through the resistors 146 and 144, issubstantially reduced, whereby placing the voltage at the base of thetransistor 142 at its most positive value, cutting off Vthe transistor142.

With the transistor 142 in' the cutoff condition, no y current flowsthrough the resistors 148, 150, and the transistor 152 is also biased tothev cutoff condition.

Similarly, with the transistor 152 in the cutoff condition,

substantially no current, flows through the transistor 154; "Thecapacitor 114 filters random noise from the output of the photocell 30and prevents such noise from interfering with circuit operation.Similarly, the capacitor 138 is used to prevent random noise fromtriggering the single-shot multi-vobrator, particularly noise from* theB side of the power supply. The function of the=vari able capacitor 116will be discussed in the succeeding paragraphs. f V- Y When the beam Ris broken, either by the passage of a bowling ball or the foot of abowler therethrough, and not received by the photocell 30, the voltageat the base of the transistor 102 is `made more positive andsimultaneously the voltage at the emitter of the transistor 102 and thebase of the transistor 108 is also made'more positive. condition and thevoltage at the collectorof the transistor 108 becomesk substantiallymore negative due tothe substantial reductionvin current flow throughthe resistor 112.

determina'ole period of timeafter the beam R has been The vtransistorlflfthereby' goes into cutoff During theoperation of the transistor 108,the variable broken, ,which said period of time may beyarcd by varyingthe-magnitude of the capacitor 116; 'With the.,k magnitudes as disclosedon Table Athe charge time for` the capacitor 116 is made substantiallylonger than the collector of the transistor 108 decrease (become more`negative) only when the beam R is broken `by something that issubstantially longer in time duration than the passage of a bowling balltherethrough.

Because the resistors 1.12 and 120 are each chosen to be substantiallyless in magnitude than the'resistor 122,l

the reduction in collector voltage of the transistor -108 will cause thevoltage at the base of the transistor 118 to become negative, therebycausing the transistor 118 to go into conduction. Prior to conduction ofthe transistor 118, the capacitor 126 will have developedV a` charge.equal to thevoltage magnitude of B- with the platethat is connected tothe collector of transistor 118 being the negative of the two plates.When the transistor 118 switches to the conducting state, its positivegoing collector voltage is coupled through capacitor 126 and resistor128 to the base of transistor 130, cutting off the operation oftransistor`130. In the manner conventional to single-shotmulti-vibrators, the transistor 130 willy remain in the cutoff state forthe period of time required for the capacitor 126 to discharge throughthe resistors 128, 132, and the potentiometer 134, and the transistor118 which'periodof time depends upon the magnitude of the capacitor 126and the resistors 128, 132, and the potentiometer 134, and not upon theperiod of time that the beamR has been broken. Therefore, once the beamRis broken for asufficient length of time for the collector voltage ofthe transistor 108 to be substantially reduced,

the remainder of the circuit operation will not be affected for a finiteperiod of time, notwithstanding that the beam R is reincident on thephotocell 30.

As the ycapacitor 126 discharges through the resistors 128 and 132, andthe potentiometer 134, the voltage at the base of the transistor 130becomes more negative with respect to the emitter thereof, and theamount of current that flows through the transistor 130 again begins toincrease to the point of saturation. Negative voltage is transferredback to the base of the'transistor, 118 from the collector of thetransistor 130 through the resistorv and holds the-transistor 118 in theconducting state until the transistor 130 reapproaches, saturation.

However, during the period of time when the voltage at the collectorofthe transistor 130 is at its most negative values, the base of thetransistor 142 achieves a sufficiently negative value to cause thetransistor 142 to go into conduction, and the transistor 142 remains inconductionuntil the` current whichv flows through the resistor l136 fromthetransistor 130 achieves a sufficient magnitude to bring the voltageat the base of the transistor 142 to zero or positive. While thetransistor 142 is in conduction,the base of the transistor v152 isbiased into conduction bythe current flowing through the resistors 148,150, from the `transistor 142. The conduction of the transistor 152causes the -base ofthe'transistor 154 to go negative involtage andthereby causes the conductionv of the transistor 154. The transistor 154stays in conduction only so long as the transistors 118, 142, and 152conduct. j This period of conduction required inbowling alleys isnominally 12 seconds `,selectively 'determined by the adjustment `of thekvoltage tap on. the potentiometer 134, which adjusts the periodv oftime required for `Vthe capacitor 126 to discharge, as previouslyexplained.

As the` transistor 154 is vbrought into conduction, it

will supplywhatever Vcurrent is lrequired toprevent its f collectorvfrom attaining ak negative voltage, thus current Y will flowv from thetransistor 154 throughthe indicator light: 68 and the secondary 160rofthe transformer 162 during each negative cycle of'voltage on thesecondary o 160, and no current will flow when the voltage on thesecondary 166 is positive with respect to ground.

The components numbered 2th? through 262 inclusive are respectivelyidentical in operation to the components i) through 162 inclusive, withthe exception that the components numbered 260 through 262 inclusiverespond to the receiving and the breaking of a beam of light Rtransmitted by the beam projector 26 above the foul line 22 on the lane12 and received by the photocell 42 in the rail 13. The breaking andreceiving of the beam R by the photocell 42 will cause the componentsVnumbered 260 through 262 inclusive to function identically as theircorrespondingly numbered components, previously described for the lane16. Thus, normally when the beam R is received by the photocell 42, thetransistors 262, 203, and 231), will be in conduction. When the beam Ris broken for a period of time sufficiently long for the variablecapacitor 216 to charge through the resistor 212, the transistor 218will go into conduction, the capac-r itor 226 will charge, thetransistor 236 will tend towards cutoif, the transistors 242, and 252,will go into conduction, and the transistor 254 will go into conductionduring negative half-cycles of voltage across the secondary 2611 of thetransformer 262. 1t should be here noted that the diodes 300, 302,prevent a decrease in voltage at one of the output terminals 42, 54,from affecting the voltage at the other terminal.

in operation, the bell ringing circuit 36 functions almost identicallyto the indicating light networks 60, '76. When both of the beams R, R',are being received respectively by the photocells 30, 42, current llowsfrom B+ to B along each of the following courses through resistor 322,320, diode 300 and resistor 112 and through resistor 322, 326, diode 302and resistor 212. As long as `the beams R, R', are undisturbed, theoperation of the components numbered 318 through 362 inclusive isidentical with the operation of the components numbered 118 through 162inclusive and the components numbered 218 through 262 inclusive. Withboth of the beams R, R', on both of lanes 10, 12, being unbroken, thetransistor 318 is held in cut-off condition, the transistor 330 has beenbiased to saturation through the resistor 332 and the potentiometer 334,the transistor 342 is biased to cut-off as the transistor 142 and thetransistors 352, 354 are also inout-off condition as are the transistors152, 154, respectively. In this condition, no current flows from theVtransistor 354 through the conventional bell 94, notwithstanding thepresence of the voltage on the secondary 369 of the step-downtransformer 362.

When either of the light rays R, R, are broken by the passage of abowlers foot through said beam, depending on which one is broken thetransistor 10S, or 208, will be cut-off and the voltage at the collectorof the particular transistor 108, 208, will decrease. This decrease involtage will cause the current through the particular diode 31N), 302,and through the resistors 322, 326, from B-lto decrease, increasing thevoltage at the base of the transistor 318 and placing the transistor 318into operation, which in turn starts the operation of the single-shotmultivibrator 88. Once the operation of the single-shot multivibrator S8commences, the components numbered 318 through 362 inclusive operateidentically with the components numbered 118 through 162 inclusiveandthe components numbered 21S through 262 inclusive when they are inoperation. It should be observed that the ca- 108 will haveV no electwhatsoever on the single-shotV multivibrator 7S and similarly, operationof the transistor 20S will have no effect whatsoever on the operation ofthe single-shot multi-vibrator network 62. However, operation of eitherof the transistors 10S, 208, will cause the indicator light ignitingnetwork associating with that particular transistor tooperate and willsimultaneously cause the operation of the bell ringing circuit 36 inparallel therewith.

When the transistor 354 goes into operation and establishes a continuouscircuit through the bell 94 andthe secondary of the transistor 362 toground, the transistor 354 behaves in a manner identical to thetransistors 154 and 254 when they are in operation in that thetransistor 354 will function in such manner as to prevent its collectorfrom going negative. Thus during the negative cycles of the voltageacross the secondary 360 of the transformer 362, the transistor 354 willsupply substantial current through the bell 94 and will maintain' thevoltage drop across the bell 94 to a magnitude suti'icient to keep thecollector of the transistor 354 always positive. This unique and novelmethod of supplying a power to a bell and an indicator light from atransistor has eliminated the need for large current supply packs andlarge transistors, and enables power to be furnisehd using a simpletransformer in combination with a transistor.

lt should be here noted that in most bowling alleys it is normal for thebell to ring for a period of 3 seconds and the lights to remain on for aperiod of l2 seconds, thus when the bell indicates that a foul has beencommitted on one of two alleys, the bowlers have an additional 9 secondsto determine on which alley the foul was committed. The period of time'for operation of the bells 94 and the lights 68, 84, may be respectivelyadjusted by adjusting the setting of the tap Von potentiometers 334,134, and 234, respectively. In addition, the taps on the potentiometers100, 200, are eective means of providing an ambient light adjustment tocompensate for varying amounts and quantities of light present on thephotocells 30, 42, respectively. l

If it is desired that the system be comprised entirely of solid statedevices, a solar cell may be substituted for the photocells 30, 42, inthe conventional manner, and a transistorized audio oscillator coupledto a speaker may be substituted for the bell 94.

It should be understood that changes, alterations and modifications inthe form, construction, arrangement and combination of parts of theamusement may be made and substituted for those herein shown anddescribed without departing from the major and principle of myinvention. For example, although we have disclosed our invention usingp-n-p type function transistors for all Ytransistors shown with theexception of transistors 152,

252, and 352, which are n-p-n transistors, n-p-n transistors may besubstituted for the p-n-p transistors and p-n-p transistors may besubstituted for the n-p-n transistors in the conventional manner.

Having thus described our invention what we claim and desire to secureby Letters Patent is stated in the following claims:

1. A foul detecting and indicating device for use with a bowling laneincluding a foul line and dened by spaced parallel rails on opposingsides thereof, Vsaid device comprising a beam projector operativelymounted on one of said rails Vand adapted for projecting a beam oflight, beam receiving means operatively mounted in the other rail forsupplying a signal when a beam of light is received' from the beamprojector, said beam projector and beam receiving means being inalignment with said foul line, amplifying means adapted for receivingthe signal from the beam receiving means andV amplifying said signal,triggering means for supplying an actuating signal when themagnitude ofthe amplified signal is substantially reduced for more thanapredetermined period of time,

A and output means including a transistor which is placed into saturatedconduction by the operation of the triggering means, a transformerhaving one winding operatively connected to a source of alternatingcurrent power and a second winding connected in series with theterminals Vof the transistor through which the saturated current owsduring conduction, and indicator means operatively connected in serieswith said second winding and said transistor terminals.

2. A foul detecting and indicating device comprising means forprojecting a beam across the foul line of a bowling lane, means forreceiving said beam, a transistor operatively connected to a source ofpower and having a base and a collector and an emitter, a transformerhaving a primary winding and a secondary winding, indicating meansadapted for operating upon application of electrical power thereto, saidindicating means and secondary winding being connected in series to theemitter and collector, said primary winding being operatively connectedto a source of alternating current electrical power, and triggeringmeans connected to said beam receiving means 10 for causing thetransistor to go into conduction when a bowler commits a foul bybreaking the beam.

3. The device of claim 2 in which the triggering means includes meansfor retaining the said transistor in conduction for a predeterminedperiod of time.

References Cited by the Examiner UNITED STATES PATENTS 2,099,764 11/ 37Touceda.

2,455,909 12/48 Smith 273-50 2,492,182 12/49 Robinson.

2,664,290 12/53 Swift 273-50 2,683,602 7/54 Dumas et al 273-50 2,782,4062/57 Krakora.

2,954,489 9/60 Brueggeman et al. 307-117 2,975,293 3/61 Kruse et al250-214 X 2,980,425 4/61 Zaander 273-43 3,029,354 4/ 62 Watkins 307-11720 DELBERT B. LOWE, Primary Examiner.

2. A FOUL DETECTING AND INDICATING DEVICE COMPRISING MEANS FORPROJECTING A BEAM ACROSS THE FOUL LINE OF A BOWLING LANE, MEANS FORRECEIVING SAID BEAM, A TRANSISTOR OPERATIVELY CONNECTED TO A SOURCE OFPOWER AND HAVING A BASE AND A COLLECTOR AND AN EMITTER, A TRANSFORMERHAVING A PRIMARY WINDING AND A SECONDARY WINDING, INDICATING MEANSADAPTED FOR OPERATING UPON APPLICATION OF ELECTRICAL POWER THERETO, SAIDINDICATING MEANS AND SECONDARY